C++ SkPaint::computeLuminanceColor方法代码示例

inline std::unique_ptr<GrAtlasTextOp> GrTextBlob::makeOp(
        const Run::SubRunInfo& info, int glyphCount, uint16_t run, uint16_t subRun,
        const SkMatrix& viewMatrix, SkScalar x, SkScalar y, const SkIRect& clipRect,
        const SkPaint& paint, GrColor filteredColor, const SkSurfaceProps& props,
        const GrDistanceFieldAdjustTable* distanceAdjustTable, GrTextTarget* target) {
    GrMaskFormat format = info.maskFormat();

    GrPaint grPaint;
    target->makeGrPaint(info.maskFormat(), paint, viewMatrix, &grPaint);
    std::unique_ptr<GrAtlasTextOp> op;
    if (info.drawAsDistanceFields()) {
        // TODO: Can we be even smarter based on the dest transfer function?
        op = GrAtlasTextOp::MakeDistanceField(
                target->getContext(), std::move(grPaint), glyphCount, distanceAdjustTable,
                target->colorSpaceInfo().isLinearlyBlended(), paint.computeLuminanceColor(),
                props, info.isAntiAliased(), info.hasUseLCDText());
    } else {
        op = GrAtlasTextOp::MakeBitmap(target->getContext(), std::move(grPaint), format, glyphCount,
                                       info.needsTransform());
    }
    GrAtlasTextOp::Geometry& geometry = op->geometry();
    geometry.fViewMatrix = viewMatrix;
    geometry.fClipRect = clipRect;
    geometry.fBlob = SkRef(this);
    geometry.fRun = run;
    geometry.fSubRun = subRun;
    geometry.fColor =
            info.maskFormat() == kARGB_GrMaskFormat ? GrColor_WHITE : filteredColor;
    geometry.fX = x;
    geometry.fY = y;
    op->init();
    return op;
}

bool GrTextBlob::mustRegenerate(const SkPaint& paint,
                                     const SkMaskFilterBase::BlurRec& blurRec,
                                     const SkMatrix& viewMatrix, SkScalar x, SkScalar y) {
    // If we have LCD text then our canonical color will be set to transparent, in this case we have
    // to regenerate the blob on any color change
    // We use the grPaint to get any color filter effects
    if (fKey.fCanonicalColor == SK_ColorTRANSPARENT &&
        fLuminanceColor != paint.computeLuminanceColor()) {
        return true;
    }

    if (fInitialViewMatrix.hasPerspective() != viewMatrix.hasPerspective()) {
        return true;
    }

    /** This could be relaxed for blobs with only distance field glyphs. */
    if (fInitialViewMatrix.hasPerspective() && !fInitialViewMatrix.cheapEqualTo(viewMatrix)) {
        return true;
    }

    // We only cache one masked version
    if (fKey.fHasBlur &&
        (fBlurRec.fSigma != blurRec.fSigma || fBlurRec.fStyle != blurRec.fStyle)) {
        return true;
    }

    // Similarly, we only cache one version for each style
    if (fKey.fStyle != SkPaint::kFill_Style &&
        (fStrokeInfo.fFrameWidth != paint.getStrokeWidth() ||
         fStrokeInfo.fMiterLimit != paint.getStrokeMiter() ||
         fStrokeInfo.fJoin != paint.getStrokeJoin())) {
        return true;
    }

    // Mixed blobs must be regenerated.  We could probably figure out a way to do integer scrolls
    // for mixed blobs if this becomes an issue.
    if (this->hasBitmap() && this->hasDistanceField()) {
        // Identical viewmatrices and we can reuse in all cases
        if (fInitialViewMatrix.cheapEqualTo(viewMatrix) && x == fInitialX && y == fInitialY) {
            return false;
        }
        return true;
    }

    if (this->hasBitmap()) {
        if (fInitialViewMatrix.getScaleX() != viewMatrix.getScaleX() ||
            fInitialViewMatrix.getScaleY() != viewMatrix.getScaleY() ||
            fInitialViewMatrix.getSkewX() != viewMatrix.getSkewX() ||
            fInitialViewMatrix.getSkewY() != viewMatrix.getSkewY()) {
            return true;
        }

        // We can update the positions in the cachedtextblobs without regenerating the whole blob,
        // but only for integer translations.
        // This cool bit of math will determine the necessary translation to apply to the already
        // generated vertex coordinates to move them to the correct position
        SkScalar transX = viewMatrix.getTranslateX() +
                          viewMatrix.getScaleX() * (x - fInitialX) +
                          viewMatrix.getSkewX() * (y - fInitialY) -
                          fInitialViewMatrix.getTranslateX();
        SkScalar transY = viewMatrix.getTranslateY() +
                          viewMatrix.getSkewY() * (x - fInitialX) +
                          viewMatrix.getScaleY() * (y - fInitialY) -
                          fInitialViewMatrix.getTranslateY();
        if (!SkScalarIsInt(transX) || !SkScalarIsInt(transY)) {
            return true;
        }
    } else if (this->hasDistanceField()) {
        // A scale outside of [blob.fMaxMinScale, blob.fMinMaxScale] would result in a different
        // distance field being generated, so we have to regenerate in those cases
        SkScalar newMaxScale = viewMatrix.getMaxScale();
        SkScalar oldMaxScale = fInitialViewMatrix.getMaxScale();
        SkScalar scaleAdjust = newMaxScale / oldMaxScale;
        if (scaleAdjust < fMaxMinScale || scaleAdjust > fMinMaxScale) {
            return true;
        }
    }

    // It is possible that a blob has neither distanceField nor bitmaptext.  This is in the case
    // when all of the runs inside the blob are drawn as paths.  In this case, we always regenerate
    // the blob anyways at flush time, so no need to regenerate explicitly
    return false;
}